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E. MÄGI, T. KASTEPÕLD & A. LOTMAN, 2004 - Ornithological monitoring and wetland management in Matsalu.
In: Anselin, A. (ed.) Bird Numbers 1995, Proceedings of the International Conference and 13th Meeting of the European
Bird Census Council, Pärnu, Estonia. Bird Census News 13 (2000):139-144
ORNITHOLOGICAL MONITORING AND WETLAND
MANAGEMENT IN MATSALU
E. Mägi, T. Kastepõld and A. Lotman
ABSTRACT. Since the establishment of the Matsalu Nature Reserve in
1957 nesting avifauna of major habitats has been monitored. the total bird
counts on Moonsund islets have been most systematic and comprehensive,
but nesting birds of the open meadows of Matsalu wetland have also been
monitored with little interruption. On the islets and in open landscape the
bird species with increasing breeding numbers are the Cormorant
Phalacrocorax carbo, Mute Swan Cygnus olor, Greylag Goose Anser anser,
Common Eider Somateria mollissima, Reed – Acrocephalus scirpaceus and
Sedge Warblers Acrocephalus schoenobaenus, Bearded Tit Panurus
biarmicus, Skylark Alauda arvensis, Meadow Pipit Anthus pratensis, Yellow
Wagtail Motacilla flava, Oystercatcher Haematopus ostralegus and Curlew
Numenius arquata. At the same time several duck and wader populations are
decreasing in numbers. The changes are partly attributable to what happens
outside the wetland - inter alia on wintering sites - and partly to stochastic
processes. However quite obviously they are at least partly caused by change
of wetland habitats in the area itself, especially overgrowth of meadows.
This has serious implications for wetland management practice and planning.
Among other measures, keeping meadow communities open is of major
importance.
Matsalu Nature Reserve, 90305 Penijõe, Lihula, Estonia
INTRODUCTION
A large number of habitats with high biodiversity found in wetlands depends on
historically grown management techniques. Extensive and often sustainable use of natural
resources has created many semi-natural habitats with high biodiversity. Balance in these
systems is fully dependent on agricultural practices and can be disrupted in at least two
directions. Both intensification of land use and abandonment of agricultural practices will
reduce the biodiversity value of the area: The former option will lead to the ‘silent green desert’
and the latter to overgrowing of the area with forest. Optimally balanced semi-natural habitats,
preserved in the Matsalu area during several hundreds of years, are now facing serious
problems.
DESCRIPTION OF THE AREA
Matsalu wetland is situated in Western Estonia. It consists of the Matsalu Bay together
with the Kasari River delta, seashore and the adjacent part of the Moonsund together with more
than forty islets. The shoreline of Matsalu Bay has a complicated pattern and there are more
than ten islets in the bay. All major watercourses flowing into the bay are connected with the
Kasari delta. The bedrock of the area is formed by Silurian limestone intersected by a
depression containing the bay and the Kasari River. Glaciation brought clay and granite to the
area, eroding also the bedrock. After retreat of the glacier, land uplift of 2 to 3 mm per year
started which is continuing today. Hence most of the shape of the delta and coastline is younger
than 500 years.
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Man has inhabited the area for several thousand years. Therefore most of the habitats have
been influenced by man since the time land emerged from the sea. This influence includes
mowing, grazing and other agricultural activities as well as forest clearing. Minor ditching
activities have also a long history here, but in the twenties and thirties (of the twentieth century)
large-scale dredging of the river delta system was carried out. These had a pronounced effect on
the wetland hydrology. Nevertheless fluctuations of the water table can still reach two meters.
The above mentioned conditions have produced high variety of habitats. They include
shallow brackish water, coastal pioneer vegetation, and extensive reedbeds, coastal, marshy and
alluvial meadows, alvars and woodlands including wooded meadows. The extraordinary
richness of the wetland nature, especially its bird fauna, was noted already more than a hundred
years ago. The Matsalu Nature Reserve was established in 1957 and was designated as
internationally important wetland area (Ramsar site) in 1975. Owing to the regaining of
independence by the Estonian Republic, designation was renewed in 1994.
Last fifty years have seen gradual abandonment of traditional agricultural practices and
hence decrease in use of semi-natural meadows. At the same time increased use of fertilisers
and concentration of animal farming into big farm complexes have created serious pollution
problems due to runoff from agriculture. The nineties have witnessed a dramatic decrease in
agricultural production. A positive side effect has been decrease in pollution of Matsalu Bay. A
serious negative consequence has been dramatic acceleration of loss of semi-natural habitats.
Management of meadow communities in the form of support for appropriate farming practices
has therefore become a chief task of the management planning and practice of the Matsalu
Nature Reserve.
The following overview presents methods and chief results of the main bird-monitoring
programmes in the following major biotopes - reed-beds, alluvial meadows, coastal meadows,
islets - and relates these to the management strategies of the Matsalu Nature Reserve.
BIRD MONITORING IN VARIOUS HABITATS
Reedbeds.
Reedbeds cover over 3 000 hectares, most of it in the inner part of the bay. Increase in the
area under reed has been more than threefold from the turn of the century due to dredging of the
delta and pollution of the bay with nutrients. The area of Common Reed Phragmites australis
monostand has increased considerably, as well as that of reed-willow swamps. The area of
mixed reedbed with patches of open water has most probably remained stable, while this
habitat, most important for many bird species, has shifted westwards. Attempts to estimate bird
numbers in the reedbeds were first made in the 1930s by E. Kumari (1937). Later researchers
include S. Onno in the 1950s, V. Paakspuu (1985) in the 1960s, G. Polma (1993) in the 1980s.
Methods include counts from boat at night, to locate singing warblers and Bitterns Botaurus
stellaris, transect and mapping counts, helicopter surveys and scan from birdwatching towers.
Methods used by different researchers are not always compatible and long-term trends must
therefore be treated with caution. Some patterns are, however, clearly evident. The most
significant changes are:
■ crash of the populations of the Black-headed Gull Larus ridibundus from 10 000 pairs in the
early 1950s to nil in the 1980s and Little Gull Larus minutus from 1 000 pairs in the 1980s
to zero in the 1960s;
■ increase in the population of the Greylag Goose from 140 pairs in the early 1960s to 250 300 in the late 1980s (Kastepõld, Mägi, 1994);
■ appearance of newcomers - Mute Swan in the 1960s (60 pairs in the late 1980s); Savi’s
Warbler Locustella luscinioides and Bearded Tit in the late 1970s and early 1980s.
The Great Crested Grebe Podiceps cristatus, Mallard Anas platyrhynchos, Pochard Aythya
ferina, Bittern, Marsh Harrier Circus aeruginosus, Black Tern Chlidonias niger appear to be
quite stable, or have possibly declined in the long run. The Reed Bunting Emberiza schoeniclus,
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Great Reed Warbler Acrocephalus arundinaceus, Reed Warblerand Sedge Warbler reveal a
more continuous increase in numbers.
The estimated numbers of the birds nesting in reedbeds are summarised in Table 1.
Table 1. Numbers of birds breeding in Matsalu reedbed in 1932-1995.
POD CRI
BOT STE
CYG OLO
ANS ANS
ANA PLA
AYT FER
AYT FUL
CIR AER
RAL AQU
POR ANA
POR PAR
FUL ATR
LAR MIN
LAR RID
CLI NIG
LOC LUS
ACR SCH
ACR SCI
ACR ARU
EMB SCH
1932-'36
(Kumari 1937)
40
25
0
160
+
225
90
40
50
+
20-25
+
1 000
5 500
260
0
+
10
84
130
1957-'60
(Onno 1963)
140
15
0
140
230
150
0
30
55
75
20
1 150
60
2 280
140
0
80
65
170
175
1968-'72
1978-'79
(Paakspuu 1985) (Paakspuu 1985)
150
140
15
18
20
25
200
200
250
>250
100
150
10
10
15
18
60
70
75
60
30
20
1 400
600
0
0
8 000
6 000
180
150
0
10
100
80
80
100
150
170
200
200
1994-'95
100
18
65
250
250
100
10
25
70
60
10
300
20
0
150
50
300
400
150
800
Alluvial meadows.
Alluvial meadows of the Kasari delta cover approximately 4 000 hectares. It is a typical
semi-natural habitat, formed in consequence of spring flooding of the river and mowing by
man. In the 1920s and 1930s the delta was dredged, which resulted in shortening of the flooding
period. Nevertheless, each spring the whole delta is flooded, and as the result of silting of the
channels, the length of natural flooding period has started to increase. During the last halfcentury mowing decreased gradually on alluvial meadows, resulting in gradual overgrowth of
more remote parts of the delta. Last years have witnessed dramatic falling out of use of the
meadows, which would inevitably lead to loss of most of the habitat, unless appropriate
measures are taken.
Bird richness of Kasari alluvial meadows was first described by V. Russow in the 1870s,
and later by H. Loudon in 1910. Further research, performed by M. Härms (1926) and E.
Kumari (1937), attempted to estimate the numbers of some meadow-birds. S. Onno (1963) and
Kuresoo et al. (1985) carried out more thorough research on bird numbers in alluvial meadows.
From 1983, E. Mägi (1993, 1994) has carried out transect counts in alluvial meadows. The last,
most long-term study served as the main basis for the following briefly summarised data
concerning the trends of the last twelve years. Comparison with other studies was performed to
obtain data on longer-term dynamics (Table 2), but should be treated with some caution due to
differences in count methods. Especially the mapping method used by Kuresoo et al. (1985)
yields a higher percentage of discovered nests and hence to higher estimates of breeding
numbers, while both the mapping method and collective counts used by S. Onno lead to higher
records of nesting ducks. As these methods are very labour- and time-consuming they have not
been used later. Comparison of the relative frequencies of different bird species is probably
more reliable in this context than comparison of absolute numbers.
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A pronounced change in the bird-fauna of alluvial meadows includes increase in openlandscape passerines: Skylark, Yellow wagtail and Meadow Pipit , both during the last twelve
years and compared with earlier study periods. Woodland passerines (e.g. Willow Warbler
Phylloscopus trochilus and Scarlet Rosefinch Carpodacus erythrinus) as well as the species
associated with high grass, bush and reeds (Sedge Warbler and Reed Bunting) are rather stable
in the long run though the latter seem to be currently on the rise (Table 2). The population crash
of waders and Corncrake Crex crex in the mid- and late 1980s was followed by slight recovery
(Table 2). The relative contribution of waders has definitely declined in long term. Only Snipe
Gallinago gallinago has totally recovered from decline, while Curlew has probably not
experienced any serious decline. The Dunlin Calidris alpina schinzii has disappeared from
alluvial meadows while Great Snipe Gallinago media has been a scarce breeder whose numbers
are hard to estimate.
Table 2. Mean density of nesting birds of Neidsaare floodplain meadow (Matsalu NR)
in breeding pairs/km².
ANA PLA
ANA ACU
ANA QUE
ANA CLY
CRE CRE
VAN VAN
CAL ALP
PHI PUG
GAL GAL
LIM LIM
NUM ARQ
TRI TOT
ALA ARV
ANT PRA
MOT FLA
ACR SCH
EMB SCH
1958-'61
3.3
2.7
0.7
0.3
1.3
11
3.3
7
3.3
19
6.3
3
5
12
9
5.3
4
1977-'80
3
2.8
8
3.2
1.5
18.8
4
31.2
21.5
16
1.5
6.5
33.2
26.2
19
61.5
6
1983-'86
1.2
0.2
5
11.3
4.3
9
10.8
16.8
0.8
7.3
17.3
15.5
12.8
12.5
4.5
1987-'92
1
0.2
0.2
2.5
4.2
2
3.2
6.2
4.8
2.3
4
22.2
18.7
21.5
9.8
37
1993-'95
1.7
1.3
2.7
2.3
4.7
1.3
10
4.3
5
2.7
37
41.3
26.3
24.3
13
Remarks: 1958-61 – mapping census + nest search (S. Onno),
1977-80 – mapping census (Kuresoo et al., 1985);
1983-95 – transect count (E. Mägi)
Coastal meadows.
Coastal meadows of Matsalu Bay and adjoining areas of the Moonsund cover about 3 000
hectares. It is a semi-natural habitat formed by brackish seawater and human influence, mostly
grazing but in some cases mowing. Sincehuman influence is as old as the coast itself here, the
area has not been naturally afforested since the retreat of the sea. Transect counts on the
meadows of southern coast of Matsalu Bay have been carried out with little interruption since
the late 1950s by S. Onno, V. Paakspuu, E. and T. Kastepõld (1990) and T. Paakspuu. Much
less data exist on the meadows of northern coast of the bay. The most pronounced changes on
both coasts include increase in the numbers of passerines, both open-landscape and other
species. Waterfowl is relatively stable on both coasts while gulls and terns are almost stable on
the southern coast and have increased on the northern coast. Waders, especially Ruff
Philomachus pugnax, Lapwing Vanellus vanellus, Dunlin and Black-tailed Godwit Limosa
limosa, have declined . Redshank Tringa totanus and Oystercatcher are relatively stable while
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Snipe has even increased. Curlew has never been numerous in our coastal meadows but appears
to be slightly increasing.
Islets.
The islets of Matsalu Bay and adjoining Moonsund areas are relatively young. Vegetation
is variable and includes reeds, pioneer vegetation, meadows, shrubs and in some cases older
woodland. Total counts of nesting birds have been conducted on the islets from 1958 on (Onno,
1963, Paakspuu, Kastepõld, 1985, Mägi et al., 1993). The bird fauna of the islets appears to be
highly dynamic. Overall nesting density and biomass have greatly increased (more than two and
ca five times, respectively). The number of nesting species is relatively stable but the evenness
of the distribution of numbers has declined in time. Few species like Eider , Herring Gull Larus
argentatus and Great Black-backed Gull Larus marinus dominate the scene now. Recent years
have witnessed dramatic increase of in Mute Swan and especially Cormorant. Bigger species
have replaced smaller ones, and especially waders have declined with exception of Ringed
Plover Charadrius hiaticula and Oystercatcher.
DISCUSSION
Considerable changes have taken place in the nesting bird-fauna of the Matsalu wetland.
The most significant changes, noted on the islets, can be partly attributed to the inherent
instability of the insular ecosystems, while some trends seem to be systematic. Successful
species (Cormorant, Mute Swan, Eider and large gulls) most probably benefit from
eutrophication that improves their feeding conditions. It should be noted that these species have
increased all over the Baltic. Large gulls benefit from the eiders and cormorants as well, feeding
on the eggs and young of the former and excess food of the latter. Decline of smaller gulls,
especially Common Gull, is probably the result of predation by larger ones. Overgrowing of the
islets with dead grass, bushes or reeds has resulted in the decline of waders. The overall decline
of evenness of numerical distribution is hard to account for.
In meadows, the most pronounces changes have been abrupt population declines that
cannot be explained by changes in local conditions. Evidently, they are associated with
disasters in wintering sites or on migration routes. However, in the long run decline of wader
species, most dependent on open semi-natural landscapes, can be observed. Long-term trends in
meadow habitats include drying up of the habitat in some cases and overgrowth with bushes or
reeds that have especially expanded recently. Several species of passerines probably benefit
from the changes that are detrimental to waders.
Some of the observed changes, particularly on the islets but also in other habitats, can be of
purely stochastic nature, which renders all explanations useless. This is most probably the case
with colonial species like Black-headed Gull whose population numbers undergo rises and falls.
Different methods used by different researches, as well as observer related biases can create
additional problems but do not appear to exert a strong effect on the main results. It should also
be noticed that a thorough statistical analysis of the data is still to be performed.
To sum up, it is quite evident that the decline of typical open-landscape waders is an
indicator of the need for more active management: mowing or grazing, and bush cutting. Best
way to do this is co-operation with local farmers. In order to assess their effectiveness, these
management measures should be co-ordinated with monitoring activities.
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CONCLUSIONS
1. Long-time bird monitoring reveals significant changes in the species composition and bird
numbers in the Matsalu wetland.
2. The most pronounced changes have taken place on the islets. These include dramatic
increase in overall nesting density and biomass, and to some extent loss of biodiversity.
3. Waders are most dependent on open semi-natural communities and show long-term
declining trends.
4. Active management of semi-natural habitatsis necessary, for which the most feasible way is
co-operation with local farmers.
5. Continuation of bird monitoring in the Matsalu wetland is necessary. It is also essential to
closely correlate monitoring with management, and to perform a more thorough statistical
analysis of the data.
REFERENCES
Härms, M., 1926. Matsalu lahe ja selle ümbruse linnustikust. - Loodusuurijate Seltsi aruanded, k. 32,
nr. 3-4, lk. 55-78.
Kastepõld, E., Kastepõld, T., 1990. Matsalu lahe lõuna- ja kaguranniku haude-linnustikust aastail 1957
kuni 1987. - Loodusevaatlusi 1988, I. Tallinn, lk.18-28.
Kastepõld, T., Mägi, E., 1994. Hallhane, Anser anser ja kühmnokk-luige, Cygnus olor pesitsemisest
Matsalu looduskaitseala, Virtsu-Laelatu-Puhtu ja Nehatu roostikes 1980-1988. Loodusevaatlusi 1993, I. Tallinn, lk. 8-19.
Kumari, E. (= Sits, E.), 1937. Materjale Matsalu lahe linnustikust. Tallinn, 328 lk.
Kuresoo, A., Laidna, A., Lilleleht, V., Renno, O., Veromann, H., 1985. Kasari luhtade linnukooslused.
Rmt.: Matsalu - rahvusvahelise tähtsusega märgala. Tallinn,
lk. 236-255.
Mägi, E., 1993. Kasari luha haudelinnustik ja selle muutumine. - Loodusevaatlusi 1992, I. Tallinn, lk.
41-63.
Mägi, E., 1994. Lindude pesitsemisest Kasari luhas. - Hirundo, nr. 2, lk. 24-31.
Mägi, E., Kastepõld, T., Paakspuu, T., 1993. Matsalu looduskaitseala Väinamere
saarte
haudelinnustiku asustustiheduse ja struktuuri muutustest. - Loodusevaatlusi 1991, I. Tallinn,
lk. 9- 16.
Onno, S., 1963. Matsalu Riikliku Looduskaitseala haudelinnustikust. - Rmt.: Ornitoloogiline kogumik,
3. Tartu, lk. 23-53.
Paakspuu, V., Kastepõld, T., 1985. Matsalu märgala vee-, soo- ja rannikulinnustik. Rmt.: Matsalu rahvusvahelise tähtsusega märgala. Tallinn, lk. 215 - 235.
Polma, G., 1993. Roostikulindude loendused Matsalu roostiku proovilappidel aastatel 1986-1988. Loodusevaatlusi 1990, I. Tallinn, 35-39.
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